Project 5.2 ... from the depths of the laboratory abyss ... ascend twin 'goth valves'

My electric exhaust dumps are similar, but they just exit below the car with no muffler.

 

Nice work Oz.

 

We're not worthy! That's really fantastic, congrats. Love it

 

The internal baffling on your mufflers must be mighty interesting as they indeed sound fabulous

 

So damn pretty. Must have a sound clip!

 

Beautiful work.

A sound clip, a dyno graph, and a price is all we need now!

 

yes....sound clip and price please..

 

That is your best one yet Oz! The bypass valves came out badass! I can hardly wait to see what inputs down, and how it sounds.

 

Pretty cool - I like the bell crank bypass design

 

Looks great!

Can't wait to see it live

 

Whoof!!!!!!!!!!, Amazing Oz

 

Impressive, to say the least.

How do you feel about the sound?


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Another Goth masterpiece!

 

Always nice to see your work Oz. Thanks for sharing!

 

Very nice! Thanks Oz!

 

Just to clarify, since Gothspeed had assumed the electric bypass I am using was on some other car than on my F355. The sound of an uncorked 355 is amazing!!! My exhaust is not as pretty as his and I have to give him much respect for creating such a nice exhaust.... I think that I prefer the vac setup over the electric setup I went with.

 

Looks Great! Will it pass smog check in California?

 

How about making a reasonably priced bypass valve to replace the OME?

 

Great. Bring one to the Stooge Fest and I can be a test case. I was going to hit you up on how to eliminate the rattle on my OME one. I've given it 4 turns to lengthen the rod but it still rattles.

 

Hi all,

Coming abit late into the party, I have been very busy driving the car since Oz left my place last night... this exhaust mod is the greatest thing I have ever done to my 355!! Seriously! I wish I had put this on 10 years ago...where were you then, Oz?

One of the main reasons I got a 355 then was plainly because of the sound it produces; even in stock form, it sounds simply awesome. Nevermind the power (or lack of it in today's standards), nevermind its drop-dead good looks, nevermind that it had some known issues when it first came out...nevermind all that but being an F1 fanatic I just loved the noise it produced. I had a couple of friends who had twin 355s in the late 90's, who always drove together and made it a point to accelerate and go through the gears at the same time as they leave the parking lot...it was as if we were all standing in the F1 pits listening to the cars pass by on the main straight! I was hooked and I knew I had to have one. But I digress.

My 355 came with a Tubi when I first got it in 2004, and while it had a great sound at WOT, I was turned off by the droning it produced as I cruised down the freeway to SoCal after picking it up in the Bay Area. I dutifully sold that system and got an MS Racing exhaust from Japan. That was an awesome exhaust, IMO, much more aggressive sounding and WITHOUT the droning at cruising speeds. It also had a very intoxicating F1 sound at WOT.

Fast forward to 2013 and the car and driver was that much older, I slowly grew out of the need for a loud exhaust that sounded aggressive all the time, I wanted something that was quite civilized and low key at low, constant throttle, enabling me to take my wife on dates again and actually have intelligent conversation inside the car. But, for those times when I am feeling delusional and the stupid racy side of me takes over, the soundtrack can change drastically from a Dr. Jeckyll to Mr. Schumacher with a flick of the paddle and a heavy right foot.

Talks with the great Oz started, and he says he believes he can deliver such a system. I described exactly what I wanted: a sport-stock level of noise in the primary system, and an all-hell-breaks-loose full F1 Insanity on bypass. Full extreme noise levels at each end, all controlled by your right foot. A split personality with absolutely NO droning please. All that while maximizing power and efficiency, and minimizing losses. That meant a completely new bypass valve design and a near straight unobstructed exhaust path in the secondaries was needed. This meant a completely separate twin bypass design to eliminate unnecessary bends in the tubing. And his usual magical concoction in that secret muffler enclosure that no one is allowed to see, that enables him to tune the sound to your specifications, without sacrificing flow. And then we also talked about other details, like the carbon fiber tips (which I was initially on the fence about) and the way it is staggered so it will appear they are equal length as they come out from underneath the bumper.

Finally, about a year later, after countless emails and text messages, he delivered. And he delivered beyond my expectations. Well beyond. The system is a work of art; with a unique radical slide valve design that completely eliminates any flow disturbance and resistance when wide open, with oversized brass bearings that eliminates any rattling.

I originally wanted to plan an install party for the system, but timing issues and other commitments came in the way. So we decided to install it right away, barely hours from completion of the system, on a late Sunday afternoon. So they came to the house and we installed the system, and Plugzit (Bruce) tagged along to supervise ;-). Bruce bailed out around 8 pm, leaving us at a point where we had just after taken out the old exhaust. I have no idea why it took that long. It took another 6 hours for me and Oz to install the new system; yeah, we finished around 2 am... I think it was the process of realigning the bumper and making sure the exhaust is centered, etc., that took so long, as we were very exhausted (no pun intended) and could not see straight anymore. LOL

The first startup was exciting, but was dampened as there were several leaks, mostly around the existing cat flanges. Tried to fiddle with them some more, but it was too late so we had to call it a night. We put the car back together, slapped the rear tires back on, and we took the car for a short spin at the local Nurburgring (i.e. a local canyon road

Nothing exciting to report at this point, as the exhaust leaks degraded the sound quality, and performance of the car wasn't up to par. We were just happy nothing fell off the car.

That is, however, about to change radically the following weekend.

 

OK, I apologize in advance for the rather boring Part 1, I understand it may not what you guys have been expecting in a thread like this... but I am so stoked that I have to record this memory somewhere!

Anyway, the saga continued the following weekend, and this past Sunday we decided to meet up again and work on the system once more. I made sure all my Mother's day commitments were well taken cared of, and so we were a go. I also made sure we met earlier in the morning so we have enough daylight left in the day.

So we put the car back up on the lift, took out some parts, and massaged the system some more, and by lunchtime, we have eliminated 99.9% of all exhaust leaks, even better than what it was originally with the previous system! Looking good so far...

After having a great lunch (prepared by the wife), we had more food for thought <g>, and we decided to check the functionality of the vacuum system that actuates the bypass system. We found that the vacuum solenoid that supplies the bypass system wasn't working, and having no spares on hand, we swapped out that solenoid with the functional one on the air injection side. I promptly ordered a new part from Ricambi; but in the meantime, I wouldn't worry about an emissions related slow down or check engine light until that solenoid is replaced.

So another test drive is in order, and this time, instead of doing the local Nurburgring, we decided to do a freeway loop so we can check acceleration and steady cruising.

Well, all I can say is SON OF A B***CH it is night and day from my previous system! At idle and light throttle, it sounds relatively low key with a subtle but authoritative throb, mostly mechanical noises are heard, but with enough exhaust notes that makes you aware that its muscles are flexed and ready for action. Drop a couple gears and squeeze on the gas and the bypass valves open and the sound becomes a pure high pitched F1 scream, like it is coming from the horn section of the philharmonic! It truly makes the car sing, it is the Pavarotti of exhaust systems! And you can hear all this INSIDE the car, and my car is a berlinetta! I cannot imagine how this sounds OUTSIDE of the car, or even on a spyder or GTS, it must be INSANE! I have heard several exhaust systems that sounded awesome outside of the car, as it drives by, or on the dyno, but nothing, NOTHING sounds like this INSIDE of the car!

My seat of the pants dyno tells me that there is a definite surge of power when the bypass opens, and cannot wait to verify this on a real dyno.

It should not affect smog legality, as long as you have it connected to OEM cats as usual. It is a bolt on system that bolts to OEM or aftermarket 355 headers, while replacing the secondary bypass system and maintaining the OEM primary catalytic converter exhaust paths. The current smog procedures does not yet require the car to run at speeds where the bypass valve opens.

It is a completely custom system, made to order to your specs. As I understand it, you can specify the loudness level of each of the primary and secondary circuit without sacrifice to flow and performance. You can even order the exhaust tips of your choice, as long as it is either stainless steel or carbon fiber ;-) It is also well built, all the pieces fitted together perfectly, with a lot of adjustability built into the design. It is a first iteration of the design, and we learned quite a bit from its install. Having said that, I think the system has arrived, and I doubt Oz will have to make any drastic changes.

I can't get enough of the car, I have been driving it since last night. Tonight I took my wife out for a ride, and she is very happy about how civilized the car sounded while we were cruising. She started talking a lot.... er, that could be a bad thing, but I digress... until... again... I dropped a couple of gears and floored the gas.... and then I heard screams, from both the exhaust and from her... and I wasn't sure which one sounded more F1 like...

So there we have it. The very first 355 exhaust that is actually wife approved. As long as you don't step on the loud pedal.

We are hoping to create some sound and video clips, but I am planning to be at the Stooge BBQ. I am happy to showcase the exhaust system, and if you are nice to me, I'd even consider giving rides.

;-)

Cheers